Electrical plug key lock



Oct. 3, 1967 s. A. COHEN ELECTRICAL PLUG KEY LOCK 2 Sheets-Sheet 1 Filed Sept. 2, 1965 FIG.I

FIG.6

INVENTOR.

STANLEY ALAN COHEN M" 4% i ATTORNEY Oct. 3, 1967 s. A. COHEN ELECTRICAL PLUG KEY LOCK 2 Sheets-Sheet 2 Filed Sept. 2, 1965 FIG? 90a F|G.8 3 i- ---IO 66a 22a 65a I03 FIGS ' INVENTOR. STANLEY ALAN COHEN ATTORNEY United States Patent thee 3,345,603 ELECTRICAL PLUG KEY LOCK Stanley Alan Cohen, 34-32 Ripple Road, Baltimore, Md. 21207 Filed Sept. 2, 1965, Ser. No. 484,630 3 Claims. (Cl. 339-176) ABSTRAQT OF THE DISCLOSURE This invention relates essentially to an electrical connector comprising a female part having a plurality of openings and an abutment in at least one of said openings and a male part having a pluralityof prongs thereon, at least one of said prongs having a detent thereon, said prong comprising a cylinder rotatable by key means.

This invention relates generally to electrical connectors, and is particularly directed to plug-and-socket type electrical connectors, such as are employed in building-wall receptacles and electrical appliances, and sometimes referred to as attachment cap and receptacle in the trade.

As is well known to those versed in the art, many electrical appliances, if not all, are more safely employed in connection with a ground wire or conductor, in addition to the usual, two-wire system. Such practice is becoming increasingly common, and it is frequently necessary at present to employ extra adapters, and other makeshift arrangements to properly connect or ground the third wire.

It has also been found advantageous to employ plugs and receptacles wherein the connection thereof may be of a positive nature so as to prohibit unauthorized, accidental or inadvertent disconnection, as for reasons of safety and otherwise.

Accordingly, it is an important object of the present invention to provide a unique construction of electrical connector which overcomes the above-mentioned difii culties and affords a grounded electrical connection, if desired, wherein the connector elements are quickly and easily joined in a positively locked condition, their juncture being severable only by deliberate and intentional ac tion of authorized persons.

It is a further object of the present invention to provide an electrical connector having the advantageous characteristics mentioned in the preceding paragraphs, which is extremely simple in construction, durable and reliable throughout a long useful life, and which can be economically manufactured, for sale and installation at a reasonable cost.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a material part of this disclosure.

The invention accordingly consits in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described, and of which the scope will be indicated by the appended claims.

In the drawings:

FIGURE 1 is a perspective view showing a wall receptacle and plug constructed in accordance with the teachings of the present invention, the plug being par tially broken away for clarity;

FIGURE 2 is an inner'end view of the plug of FIG- *URE l, as taken along the direction of line 2-2.

FIGURE 3 is a longitudinal sectional view showing the socket and plug of FIGURE 1 in their connected condition;

3,3456% Patented Oct. 3, 1967 FIGURE 4 is a front elevational view showing the inner section of a receptacle of the present invention, as taken along the 4-4 of FIGURE 3;

FIGURE 5 is a rear perspective view showing the front or cover section of the receptacle of FIGURE 3;

FIGURE 6 is a longitudinal elevational view, partly in section, showing a ground-prong construction of the plug of FIGURES 1-5;

FIGURE 7 is a front perspective view showing a slightly modified form of electrical receptacle and plug constructed in accordance with the teachings of the present invention;

FIGURE 8 is a sectional view taken through the connected plug and receptacle of FIGURE 7, in the locked condition thereof;

FIGURE 9 is a partial view similar to FIGURE 8, but illustrating an early stage in the operation of separating the plug and receptacle; and

FIGURE 10 is a partial sectional view taken generally along the line 10-10 of FIGURE 8.

Referring now more particularly to the drawings, and specifically to FIGURES 1-6 thereof, a building wall is there generally designated 20, and mounted therein is a receptacle or socket 21 constructed in accordance with the teachings of the present invention. A plug of the present invention is generally designated 22, and includes a conduit 23 containing the necessary electrical conductors or wires.

.The plug 22 is best seen in FIGURES 2 and 3 and includes a generally cylindrical male part or body 25 having a central thru hole 26 receiving the conduit 23. A pair of laterally spaced prongs 27 and 28 project generally normal to and inward from the part 25, being respectively provided with ears 29 and 30 suitably anchored to the part 25, as by rivets 31 and 32, or other suitable fastening means. Carried by the ears 29 and 30 are connector posts or screws 33 and 34 respectively connected to wires 35 and 36 of conduit 23, in the conventional manner.

The male part or body 25 is further provided with an additional, inwardly projecting prong, generally designated 4%, which may extend generally parallel to the prongs 27 and 28. The construction of prong 40 is best seen in FIGURE 6 as being internally hollow and having longitudinally extending diametrically opposed slots 41 and 42. A platelike catch or detent 43 is mounted in the hollow prong 40, being pivotally mounted therein as by a pin 44, and is formed with a generally triangular extension 45 having an oblique or sloping inner edge 46, and a perpendicular or normal outer edge 47, both relative to the longitudinal dimension of the prong 40. Internally of the hollow prong 4t? may be provided a rollable ball 48 resiliently urged by a coil compression spring 49 into engagement with an edge of detent 43 to urge the latter to its solid-line position shown in FIGURE 6. Against the force of spring 49 the detent 43 may be swung upward, about the pivot 44, to its phantom position shown in FIGURE 6.

The forward or outer end of prong 40 assumes the configuration of a cylinder-lock plug, which may be an integral extension of the prong, and is formed with -a keyreceiving slot 51 opening forwardly, for a purpose ap pearing presently. A tumbler cylinder 52 rotatively surround and journals the plug 50, and includes tumblers 53 in operative relation with the plug. The plug is retained in the cylinder 52 by suitable retaining means, such as ring 54, to permit relative rotation of the plug within the cylinder, without relative longitudinal movement thereof.

The prong assembly of FIGURE 6 is incorporated in the male part or body 25 by fixedly securing the tumble-r cylinder 52 in the body, with the prong projecting from the body in spaced parallelism with the prongs 27 and 28. In addition, an electrical connection is made to the prong 40, as by an arm 55, see FIGURE 2, having an car 56 provided with a connector post or screw 57. A ground conductor or wire 58 from the conduit 23 may be connected to the post 57. The arm is advantageously electrically connected to the cylinder 52, as the prong 40 and plug 50 are rotatable relative to the body part 25, while the cylinder is fixed relative to the body part.

The receptacle 21 may include a mounting bracket 60, of generally U-shaped configuration receiving a female part, generally designated 61, and having ears 62 and 63 for securement to the wall 20. The female part 61 includes an inner section 65, which may advantageously be molded of plastic, or otherwise suitably formed, and is formed with a plurality of forwardly or outwardly facing recesses, including a pair of side-by-side, laterally spaced recesses 66 and 67, which may be substantially identical but of opposite hand, and an additional recess 68 located centrally above the first-named pair of recesses, best seen in FIGURE 4. The recesses 66 and 67 each include contact means, respectively designated 69 and 70, also substantially identical but of opposite hand. The contact means 69 may include an arrangement of forwardly extending resilient leaves 71 deflectable for snug reception of prong 27, while the contact means may include a similar arrangement of resilient, forwardly extending leaves 72 for frictional receiving engagement with prong 28. In addition, the contact means 69 may include an extension or arm 73 carrying a connector post or screw 74, while the contact means 70 may include a similar extension or arm 75 carrying a connector post or screw 76.

Additional contact means is provided in the upper recess 68, including a pair of facing, spaced resilient leaves 81 extending forwardly from the bottom wall of the recess 68, being suitably anchored thereto by fastener means, such as rivet 82. As seen from the front, see FIG- URE 4, the contact arms or resilient leaves 81 are downwardly diverging configuration, advantageously having their lower extremities curved outward, away from each other, as at 83. In addition, an extension or arm 84 extends from the contact leaves 31 to a location externally of the section 65 where it is provided with a connection post or screw 35.

The female part 61 includes a forward or outer section 86, best seen in FIGURES 3 and 5, configured to conformably engage in covering relation across the front of the inner section 65, and having respective thru holes 87, 88 and 89 for alignment with recesses 66, 67 and 68. Thus, the thru holes 87 and 88 receive prongs 27 and 28, while the hole 89 receives prong 40. The hole 89 is provided on its inner lower side with an inwardly facing shoulder or abutment 90, see FIGURE 3. Further, the upper bounding region of hole 89 is cut away, as at 91, so that the hole 89 assumes a somewhat inverted keyhole-shaped configuration.

With the cover section 86 secured in position in front of the inner section 65, and a wall plate 92 secured about the cover section 86 and to wall 20, the plug 22 may be engaged in the receptacle 21. As best seen in FIGURE 3, insertion of prong 40 through hole or opening 39 effects upward pivoting of detent 43 and snap engagement thereof inward to the position shown in FIGURE 3. In this position, the detent edge 47 has swung downward for edge engagement with abutment to positively prohibit withdrawal of prong 40 from opening 89. However, upon rotation of prong 40 approximately 180 degrees, or one-half turn, the detent extension 45 will align with the cutout 01 and the prong may be withdrawn. For this purpose, the key 95 may be inserted into key slot 51 and the plug 50 rotated together with prong 40. However, if desired, the provision of a tumbler-lock mechanism may be eliminated, and any 4- suitable knob, dial or the like employed to effect rotation of prong 40.

In the embodiment of FIGURES 7l0, there is provided a receptacle 21a in wall 20a, and a plug 22a for insertion and withdrawal relative to the receptacle. The receptacle 21a and plug 22a may be substantially identical to the receptacle and plug of the first-described embodiment, except for the ground-connection elements.

As best seen in FIGURE 8, the inner section 65a of female part 61 may have a recess 63a containing contact means 80a. The contact means 80a may assume the configuration of a U-shaped member having its bight portion suitably secured, as by a rivet 101 to the bottom of recess 68a, and may have a pair of legs 102 extending forwardly r toward the cover section 36a of the female part. As best seen in FIGURE 10 the legs 102 are located in facing spaced relationship; and, on the forward end of each leg may be provided an inturned portion or abutment 90a.

The plug 22a includes a prong 40a having an enlarged end portion or head 43a on a reduced shank 103. The inner end of the enlarged head 43a may be somewhat concave, as at 47a, if desired. Thus, the prong 40a is insertable into the recess 68a, with the enlarged head 43a engaging the inwardly convergent abutment portions 90a to displace the latter outward away from each other and permit continued inward insertion of the enlarged portion 43a beyond the abutments 90a, whereupon the latter snap back toward each other and effect positive retention of the enlarged portion within the recess 68a.

Mounted on the shank 103 of prong 40a is a generally cylindrical operating element or sleeve 104. The sleeve 104 serves as an operating element, as will appear presently, and is formed with an oblique or spiral cam slot 105 receiving a pin 106 projecting radially from the shank 103. The sleeve 104 is also provided with a radially projecting rib or lug 107 engageable in a slot 108 formed internally of the female part cover section 86a and constraining the sleeve to longitudinal sliding movement along the shank 103. Upon rotation of the prong 40a, as by actuation of key 95a, the sleeve 104 is constrained to longitudinal movement and motion of the sleeve is effected by pin 106. Upon inward movement of the sleeve 104 from the position of FIGURE 8 to that of FIGURE 9, the sleeve engages with and displaces the abutments 90a outward away from each other, out of the path of withdrawal of the enlargement or head 43a. The prong 40a may then be readily withdrawn, as desired.

From the foregoing, it is seen that the present invention provides an electrical-connector construction which fully accomplishes its intended objects and is well adapted to meet practical conditions of manufacture, installation and use.

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. An electrical connector comprising a female part having a plurality of inwardly extending openings, electrical-contact means in each of said openings, an inwardly facing abutment in at least one of said openings, a male part, a plurality of prongs on said male part respectively insertable in said openings for engagement with said contact means, and a detent on at least one of said prongs for retaining engagement with said abutment upon said insertion; in combination with means mounting said one prong for selective shifting to move said detent out of engagement with said abutment, for withdrawal of said male part and prongs; said mounting means comprising a cylinder in said male part supporting said one prong for rotative shifting; said female part comprising an inner section having recesses defining the inner ends of said openings, said contact means being located in said recesses, and an outer section covering said inner section and having thru holes in respective alignment With said recesses, said outer section having an internal shoulder adjacent to one of said holes and defining said abutment, and said one hole having a cutout spaced from said abutment for passing said detent upon rotation of said one prong.

2. An electrical connector according to claim 1, in combination with lock-tumbler means carried by said male part in operative association with said cylinder, and a keylock plug fixed to said one prong and rotatably supported in said cylinder for rotation responsive to key actuation.

3. An electrical connector comprising a female part having a plurality of inwardly extending openings, electrical-contact means in each of said openings, an inwardly facing abutment in at least one of said openings, a male part, a plurality of prongs on said male part respectively insertable in said openings for engagement with said contact means, and a detent on at least one of said prongs for retaining engagement with said abutment upon said insertion; said abutment being displaceable out of the path of said detent, and displacing means on said one prong for displacing said abutment out of the path of said detent, for withdrawal of said prongs from said openings; said displacing means comprising an operating element mounted for movement along said one prong into and out of displacing relation with said abutment, and actuating means in said male part for effecting movement of said operating element.

References Cited UNITED STATES PATENTS 1,771,757 7/1930 Keeper 33975 2,203,973 6/ 1940 Walls.

FOREIGN PATENTS 423,608 10/ 1924 Germany.

FRANCIS K. ZUGEL, Primary Exlaminer.

I. H. MCGLYNN, Assistant Examiner. 

1. AN ELECTRICAL CONNECTOR COMPRISING A FEMALE PART HAVING A PLURALITY OF INWARDLY EXTENDING OPENINGS, ELECTRICAL-CONTACT MEANS IN EACH OF SAID OPENINGS, AN INWARDLY FACING ABUTMENT IN AT LEAST ONE OF SAID OPENINGS, A MALE PART, A PLURALITY OF PRONGS ON SAID MALE PART RESPECTIVELY INSERTABLE IN SAID OPENINGS FOR ENGAGEMENT WITH SAID CONTACT MEANS, AND A DETENT ON AT LEAST ONE OF SAID PRONGS FOR RETAINING ENGAGEMENT WITH SAID ABUTMENT UPON SAID INSERTION; IN COMBINATION WITH MEANS MOUNTING SAID ONE PRONG FOR SELECTIVE SHIFTING TO MOVE SAID DETENT OUT OF ENGAGEMENT WITH SAID ABUTMENT, FOR WITHDRAWL OF SAID MALE PART AND PRONGS; SAID MOUNTING MEANS COMPRISING A CYLINDER IN SAID MALE PART SUPPORTING SAID ONE PRONG FOR ROTATIVE SHIFTING; SAID FEMALE PART COMPRISING AN INNER SECTION HAVING RECESSES DEFINING THE INNER ENDS OF SAID OPENINGS, SAID CONTACT MEANS BEING LOCATED IN SAID RECESSES, AND AN OUTER SECTION COVERING SAID INNER SECTION AND HAVING THRU HOLES IN RESPECTIVE ALIGNMENT WITH SAID RECESSES, SAID OUTER SECTION HAVING AN INTERNAL SHOULDER ADJACENT TO ONE OF SAID HOLES AND DEFINING SAID ABUTMENT, AND SAID ONE HOLE HAVING A CUTOUT SPECED FROM SAID ABUTMENT FOR PASSING SAID DETENT UPON ROTATION OF SAID ONE PRONG. 